In 1987 Barrett became involved in Family Solidarity, a movement established to resist the liberal-globalist attack on the family. From 1992 he became a leader in the Irish pro-life movement, becoming the lead spokesperson of Youth Defence. In this capacity he was also involved in the campaign against the 2002 abortion referendum.
In 2001, Barrett campaigned against the Nice Treaty referendum  - a vote which was sensationally rerun so the Irish establishment could garner the result the EU elites intended. During the second Nice campaign, Barrett became the centre of a bitter media attack over links to what was described by the media as "neo-Nazi" movements in Germany.
Barrett's unwavering position on nationalist and patriotic issues  invited persistent attacks from the liberal elite which culminated in a failed attack on him during a debate at UCD. He was unhurt in the altercation.
Barrett withdrew from public life shortly after the 2004 European Elections.
- Killilea, Gayle (October 7th, 2001). "The man wired to fight abortion". Irish Independent. http://www.independent.ie/opinion/analysis/the-man-wired-to-fight-abortion-26251153.html. Retrieved 2013-06-26.
- Donaghy, Kathy (October 12th, 2002). "Campaigners on both sides of treaty lash out at Barrett". Irish Independent. http://www.independent.ie/irish-news/campaigners-on-both-sides-of-treaty-lash-out-at-barrett-26030728.html. Retrieved 2013-06-26.
- Hughes, Michael P (October 18th, 2004). "Attack on Mr Barrett". Irish Independent. http://www.independent.ie/opinion/letters/attack-on-mr-barrett-25893372.html. Retrieved 2013-06-26.